Prognostic Meteorological Discussion
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FXAK02 KWNH 251841
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ALASKA EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
241 PM EDT SAT MAR 25 2017

VALID 12Z WED MAR 29 2017 - 12Z SUN APR 2 2017

THE BEGINNING OF THE FORECAST PERIOD LOOKS TO START OFF WITH A
BROAD UPPER TROUGH OVER MUCH OF THE STATE WITH LARGE-SCALE RIDGING
WEST OF THE STATE AND INTO SIBERIA.  THE UPPER LEVEL TROUGH
WEAKENS AND LIFTS NORTHWARD BY WEDNESDAY AS A DEEP CLOSED LOW
APPROACHES THE WESTERN ALEUTIANS FROM THE SOUTHWEST.  THIS LOW
SHOULD MOVE EAST/NORTHEASTWARD WITH TIME CROSSING THE CENTRAL TO
EASTERN ALEUTIANS BY FRIDAY.  THE MODELS AND ENSEMBLE MEANS ARE IN
REASONABLY GOOD AGREEMENT WITH THE HANDLING OF THE SYNOPTIC SCALE
FEATURES WITH SOME MINOR TIMING AND INTENSITY DIFFERENCES.  A
BLEND OF THE EURO AND GEFS ENSEMBLE MEANS THROUGH THE PERIOD
PROVIDED A GOOD STARTING POINT ON PLACEMENT FOR BOTH THE SURFACE
AND 500MB PROGS, WHICH IS CLOSE TO WPC CONTINUITY FROM YESTERDAY.
IN TERMS OF INTENSITY, THE DETERMINISTIC GFS, EURO, AND CMC
CONTINUE TO ADVERTISE THE ASSOCIATED SURFACE LOW DROPPING WELL
INTO THE 960S.  THEREFORE, SOME OF THE DETERMINISTIC GUIDANCE WAS
INCLUDED IN THE BLEND TO DEPICT A STRONGER INTENSITY THAN IS SHOWN
BY THE ENSEMBLE MEAN GUIDANCE AND THE MANUAL PROGS WERE ADJUSTED
FURTHER TO ACCOUNT FOR THIS.

IN TERMS OF SENSIBLE WEATHER, MOST OF CENTRAL AND NORTHERN ALASKA
SHOULD REMAIN DRY DURING THIS TIME WITH SURFACE HIGH PRESSURE
ACROSS THE NORTHERN THIRD OF THE STATE.  FOR THE MIDDLE OF NEXT
WEEK, PRECIPITATION SHOULD BE MAINLY CONFINED TO THE SOUTHERN
COAST AND THE ALEUTIANS AS A STORM SYSTEM WEAKENS OVER THE GULF.
TOWARDS THE END OF THE WEEK, THE LARGE STORM SYSTEM PREVIOUSLY
DESCRIBED APPROACHES THE ALEUTIANS WITH PRECIPITATION INCREASING
FOR FRIDAY AND INTO NEXT WEEKEND FOR THE SOUTHERN THIRD OF THE
STATE, AS THE STORM MOVES INTO THE NORTHERN GULF OF ALASKA AND
THEN WEAKENS OVER WESTERN ALASKA.  VERY WINDY CONDITIONS ARE
LIKELY NEAR THE COAST, ACROSS THE ALEUTIANS, AND ESPECIALLY OVER
THE OFFSHORE WATERS WITH STORM FORCE WINDS LIKELY.  IN THE
TEMPERATURE DEPARTMENT, EXPECT A GRADUAL MODERATING TREND IN TEMPS
BY THE MIDDLE AND END OF NEXT WEEK AS THE UPPER LEVEL TROUGH
BEGINS RETREATING TOWARDS THE NORTH.  AREAS NORTH OF THE BROOKS
RANGE WILL LIKELY REMAIN QUITE COLD AS THIS REGION SHOULD STAY
NORTH OF AN ARCTIC FRONTAL BOUNDARY.

D. Hamrick

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